1700 ps = nm tunable dispersion compensation for 10 Gbit = s RZ lightwave transmission

Introduction: Tunable dispersion compensation is becoming inevitable for fibre-optic communication systems. Important applications include replacing conventional dispersion compensating fibres (DCFs) in long-haul transmissions, compensating residual dispersion after the DCF to meet the tight dispersion tolerances required in 40 Gbit=s and above based networks, and compensating thermallyinduced variations in dispersion which can be as large as 30 ps=nm [1]. Moreover, it is known from the theory that for high data rate transmission, return-to-zero (RZ) signalling formats are superior to the non-return-to-zero (NRZ) signalling formats, owing to their increased robustness to many distortions from fibre propagations [2]. Previous works on tunable dispersion compensation for RZ signal transmissions include nonlinearly-chirped fibre Bragg grating [3] and multicavity etalon [4] based tunable dispersion compensators (TDCs). However, the tuning range of these works is limited to 250 ps=nm. Recently, we have demonstrated a TDC capable of producing a tuning range of 2040 to þ850 ps=nm using a transmission setup with 10 Gbit=s positively chirped NRZ signals [5]. Here, we extend our work to demonstrate tunable chromatic dispersion compensation for 10 Gbit=s RZ signal transmissions with different pulse durations using standard SMF up to 100 km ( 1700 ps=nm).